My friend bought a beautiful hydrangea bush and planted it in his garden. But after some time, he noticed that the leaves were slowly turning brown. So, he contacts me to know what is happening to his beautiful hydrangea plant. As an experienced home gardener, I knew immediately what the issues could be.
There are various reasons hydrangea leaves might turn brown, and there are also treatments for each.
Causes and Treatment of Hydrangea Leaves Turning Brown
If your hydrangea leaves turn brown, act quickly to determine the cause and begin treatment. You can bring your hydrangea plant back to good health with a little care and prevent the leaves from turning brown again.
1. Overwatering
The most common cause of hydrangea leaves turning brown is overwatering. When you water your plants too much, the roots can’t get enough oxygen and start to rot. Overwatering will cause the hydrangea leaves to turn brown and wilt.
It would be best to stop watering your plant for a few days to fix this. Once the soil has dried out, you can water it properly. Ensure that you water your plant only when the soil is dry.
2. Underwatering
If the leaves turn brown, it could be a sign that the plant isn’t getting enough water, which is one of the most common reasons why leaves turn brown. So be sure to water your plants regularly, ensuring the soil is always moist. Avoid letting the soil dry out completely, as this can cause the leaves to die and fall off.
3. Soil Type Doesn’t Suit Your Hydrangea Plant
When it comes to the causes of hydrangea leaves turning brown, the soil type is a major one. The leaves will turn yellow-green and brown if your hydrangea is planted in ‘too rich’ and moist soil. The best way to combat this is by planting your hydrangea in soil draining well and using a soil amendment like compost or bark mulch to keep the soil pH in check.
4. Fungal Diseases
Fungal diseases are another reason hydrangea leaves turn brown. Fungi are everywhere—in the air, in the soil, on the leaves of plants—and all it takes is the right combination of temperature and moisture for them to start growing.
Two types of fungi commonly affect hydrangeas: powdery mildew and leaf spot. Powdery mildew looks like, you guessed it, powder on the plant’s leaves and usually appears in late summer or early fall. Leaf spot is characterized by small, dark spots on the leaves and can occur at any time during the growing season.
You can treat both of these diseases with fungicides, but the best way to prevent them is to water your plants at the roots (not from overhead) and ensure they have good air circulation.
5. Bacterial Diseases
If you notice your hydrangea leaves turning brown and mushy, it could be because of a bacterial disease called bacterial wilt. It occurs when bacteria from the Pseudomonas syringae pv, and syringae enter the plant through wounds in the leaves or stem.
The bacteria then multiply, causing the plant to wilt and the leaves to brown. If you think your plant has bacterial wilt, you’ll need to take it to a professional for treatment.
6. Poor Drainage
It could be a drainage issue if your hydrangea leaves turn brown and wilting. If the roots of your plant sit in water, they will start to rot, which will cause the leaves to turn brown and die.
The easiest way to fix this problem is to repot your hydrant into a pot with drainage holes.
Once you’ve done that, ensure you’re watering your plant regularly, not letting it sit in water. If you see the leaves starting to turn brown again, it’s time to inspect your watering habits.
7. Pests
Pests are one of the reasons your hydrangea leaves might be turning brown. The most common pests that attack hydrangeas are aphids, scales, and mites. These little buggers will suck the sap out of your plant, causing the leaves to turn brown and eventually die.
If you see any pests on your plant, the best thing to do is to remove them by hand. You can also use a pesticide, but choose one safe for plant use. You can also try using a homemade mixture of soap and water to eliminate the pests.
8. Nutrient Deficiencies
Hydrangeas are heavy feeders and need to be fertilized regularly, especially when they are actively growing in the spring and summer. If you see the leaves turning brown, it could be a sign that your plant is not getting enough nutrients.
The best way to fix this problem is to give your hydrangea a good fertilizer high in nitrogen. You can also add some compost to the soil to help provide the nutrients that your plant needs.
If nutrient deficiencies are the problem, it is best to take a soil sample to your local extension office to have it tested. The soil will be tested, and they will tell you exactly what nutrients are lacking and how much needs to be added.
9. Excessive Sun Exposure
If you notice that the leaves on your hydrangea are turning brown and crispy, it could signify that they’re getting too much sun. Hydrangeas like to be in partial shade, so if they’re in an area that gets full sun all day long, it can cause the leaves to scorch.
To fix this problem, you’ll need to move your plant to an area that gets less sunlight. Try to find an area where the plant will get some morning sun but will be shaded by the hot afternoon sun.
10. Winter Damage
Winter damage is another possible reason for your hydrangea leaves turning brown. This usually happens when the plant doesn’t have enough time to harden off before the first frost, causing the leaves to turn brown and die.
If you live in an area with harsh winters, it’s best to plant your hydrangeas in the spring, so they have plenty of time to grow and harden off before the cold weather hits. You can also try wrapping them in burlap or placing a mound of mulch around the base of the plant to help protect it from the cold.